1. Field of the Invention
The present invention relates to a raw material kit for an electrolytic composition, an electrolytic composition obtained from the raw material kit for an electrolytic composition, and a dye-sensitized solar cell using the electrolytic composition.
2. Description of the Related Art
The general construction of a dye-sensitized solar cell is described in, for example, Jpn. Pat. Appln. KOKAI Publication No. 1-220380. As described in the prior art quoted above, the solar cell comprises an oxide electrode including a transparent semiconductor layer containing fine particles of a metal oxide and a dye supported on the surface of the transparent semiconductor layer, a transparent electrode arranged to face the oxide electrode, and a liquid carrier movement layer interposed between the two electrodes noted above. The solar cell of the particular construction is called a wet type dye-sensitized solar cell because the carrier movement layer is a liquid.
The dye-sensitized solar cell outlined above is operated as follows. Specifically, the light incident on the transparent electrode runs to reach the dye supported on the surface of the transparent semiconductor layer so as to excite the dye. The excited dye promptly delivers electrons to the transparent semiconductor layer. On the other hand, the dye that is charged positive because of the loss of the electrons receives electrons from ions in the carrier movement layer, thereby the dye is electrically neutralized. The ions that have delivered the electrons are diffused into the transparent electrode, thereby the ion received the electrons. The oxide electrode and the transparent electrode perform the functions of the negative electrode and the positive electrode, respectively, so as to allow the wet type dye-sensitized solar cell to perform its function.
A solvent having a low molecular weight is used in the wet type dye-sensitized solar cell. In order to prevent the leakage of the liquid, it is necessary to shield strictly the wet type dye-sensitized solar cell. However, it is difficult to maintain the shielded state for many years, with the result that it is worried about that the cell performance may be deteriorated and an adverse effect may be given to the environment by the loss of the solvent caused by evaporation of the solvent and by leakage of the solvent. Under the circumstances, it is proposed to use a solid electrolyte layer having an ionic conductivity or an electron conductivity, which does not contain a solvent, in place of the liquid carrier movement layer. A solar cell of this type is called an all solid dye-sensitized solar cell.
The problem of the liquid leakage need not be worried about in the solid dye-sensitized solar cell. However, a new problem is generated in the solid dye-sensitized solar cell. Specifically, the semiconductor electrode such as the oxide electrode and the solid electrolyte layer differ from each other in the thermal expansion coefficient, with the result that the solid electrolyte layer tends to be peeled off from the semiconductor electrode during the heat cycle. It follows that the energy conversion efficiency is deteriorated.